Do Cockroaches Eat Other Cockroaches?

Cockroaches are a pest that is known for eating anything. This can include other roaches. Cannibalism is a disturbing trait to many, but loyalty to their species has never stopped a roach from picking their own survival over others in their colony.

Roaches do eat other cockroaches. However, cannibalism is usually a last resort, motivated by outside factors. For example, if a roach has no other food, is overcrowded in a nest, is lacking in nutrients, or has a mating dispute. Larger roaches will then be driven to eat their young, their eggs, smaller adults, or even other insects. Cockroaches of all ages may eat dead cockroaches and shed skins as well.

The main motivation will always be survival and preservation. As such, roaches will prefer to eat other dead insects, instead of fighting live ones. If things are truly dire, they may even consume their own poop, but will die from starvation anyhow. In some cases, you can leverage a roach’s cannibalistic tendencies to your advantage. Poisoned traps can send in tainted roaches to then poison the full colony once eaten. 

Do Cockroaches Eat One Another?

Cockroaches eat just about anything, including each other. It will not be their first instinct, however. Roaches will not choose their own kind over more plentiful food. That’s because roaches are scavenging insects, rather than hunters. In the wild, they rely on eating:

  • Rotted wood
  • Decaying leaf matter
  • Fruits, berries, or other vegetation that’s started to rot
  • Animal carcasses or the bodies of other insects

In the average home, they will much prefer leftover food, organic waste like hair, or trash. The time, effort, and danger of contending with live food that can fight back are too much.

Nonetheless, cockroaches are resilient creatures that will not accept starvation if some other resource is at all available. This can drive them to biting humans, pets, and even eating each other. Let’s explore the 4 motivating factors:

Overpopulation

Roaches live in colonies with a large population. So long as there’s ample space to contain all members of the nest, they will exist in harmony. In fact, they will leave scent trails to guide new members to food and shelter, expanding their numbers. With that said, overpopulation leads to overcrowding, where not all members will have access to:

  • Shelter
  • Water
  • Food
  • Protection from the elements

In these cases, you’ll find that roaches naturally thin out their colony. Large roaches will take it upon themselves to eat smaller members to create more room. Any that have injuries or lost limbs, which make it difficult for them to escape or fight back, will fall victim. It’s survival of the fittest.

do cockroaches eat their dead?

A Lack of Food

If roaches live in a home that’s well cleaned and free of exposed leftovers, they will be in dire need of food. This mounting hunger will encourage roaches to eat whatever is nearby – which is often other members of their colony. In the later stages of an extermination plan, you may find the population cannibalizing itself out of desperation. This can be a good sign, indicating that your efforts are working.

On the other hand, if you haven’t practiced any pest control, it’s a sign that the population has grown astronomically. More specifically, to the point where the food sources available aren’t enough to sustain the colony.

Harsh Conditions

Roaches can thrive in nearly any conditions on the planet. With that said, they are cold-blooded creatures that are unable to create their own body heat. If temperatures drop to or below freezing, their metabolism will begin to slow down.

This may not kill them. However, it will make the cockroaches struggle to produce the energy they need to function, let alone thrive. To compensate, they’ll turn to cannibalism. That’s why you may find roaches cannibalizing each other in the winter months, or in areas where they can’t find appropriate warmth. They need nutrients, and other members of their species will suffice.

Mating Conflicts

Spiders and praying mantis are not the only creatures where females can eat the males during mating. Some cockroach species will see the female turn on the male and devour him.

This is a rare behavior, but usually has a clear motivation. The female may deem her nutrient stores as lacking. Though most roaches don’t carry their young inside a womb, they still need to devote resources to the eggs. If the female is unable to do this, she may seek out other members of her species to make up for the deficiency.

According to the Asian Food Science Journal, cockroaches offer a decent amount of nutrients. One roach can offer:

  • Moisture content
  • Crude ash
  • Crude protein
  • Fiber
  • Carbohydrates
  • Nitrogen extract

That’s not to mention the nutrients found in rarer species of cockroach, the likes of which can produce milk.

Do Cockroaches Eat Other Dead Cockroaches?

In line with their cannibalistic tendencies, a roach will eat other dead cockroaches. It’s not just a self-preservation tactic, nor is it a meaningless desecration of a corpse. This habit actually benefits the greater ecosystem.

Biotropica explains that cockroaches are a clade of detritivore-herbivore insects. Other sources also claim that cockroaches are omnivorous. What this means is that cockroaches are able to, and will, eat detritus. This includes leaf litter, rotting fruit, and decaying bodies. That ensures that cockroaches recycle what other animals leave behind.

In digesting this matter, cockroaches process it and turn it into waste which fertilizes the earth for new growth. Instead of leaving dead cockroaches to uselessly waste away, live roaches can tidy up the mess. This ensures nitrogen is properly released into the air, helping the environment.

With that said, roaches won’t immediately eat their own dead. That’s because, upon death, cockroach bodies release oleic acids. These are fatty acids that produce a ‘death scent’ to warn other cockroaches away from potential danger.

Over time, this scent fades away. If nearby roaches are hungry, and the scent is powerful enough, they will overcome their fear. The corpse presents free food that doesn’t require a fight, and they’ll take that opportunity.

Do Cockroaches Eat Their Young?

According to the Journal of Economic Entomology, cockroaches eat their young. These baby roaches are called nymphs. It is suggested that by eating young, cockroaches are self-regulating their population. After all, if there are more individuals in a colony, the resources can become strained.

However, most roaches don’t seek out their young as easy meals. They will be driven to it. This is for the same reasons as described above, with some bonuses:

Nymphs Can’t Fight Back

As mentioned, roaches aren’t hunters and don’t like to fight their food sources. Because of this, nymphs make easy meals when cockroaches are driven to seek out live prey.

Depending on their stage of development, the nymphs may not have great motor function. Likewise, their smaller bodies mean they can’t bite back with the same intensity. If they’re newly hatched, they may not even see the attack coming.  

Certain species have a defense mechanism in place for this exact reason. For example, German cockroach nymphs actually produce a pheromone that repels adult cockroaches.

Nymphs Have Soft Exoskeletons

Roaches will molt several times throughout their lives. However, the majority of these will happen right after they’re hatched. During these first molts, roaches are left vulnerable. They shuck off their hard exoskeleton and survive for several minutes or hours with only a soft layer of skin.

This skin will then harden into a protective shell. The weak jaws of other adults will be unable to damage it. In the meantime, however, this new skin is very easy to tear, puncture, and bite through. While an adult may survive a fellow roach attack, a nymph will be torn apart almost immediately.

Nymphs Aren’t As Quick To Escape

Nymphs lack the speed or agility of their older counterparts. As a result, when overpopulation or starvation turns a colony to cannibalism, nymphs can’t properly flee. At the least, they won’t escape as quickly as other small roaches. This makes them the first – and usually final – targets. 

With all that said, some cockroaches do maintain paternal instincts. Several species, including giant northern cockroaches, care for their young. They will even forage for food and bring it back to the nest for the young to eat.

Do Cockroach Nymphs Eat Each Other?

The majority of cockroach species are independent creatures. The young will hatch, molt, and feed themselves without help or care from adults. As a result, it’s no surprise that some nymphs will also eat each other to fill a nutrient gap.

This is supported by The Journal of Insect Physiology. Here, it’s stated that cockroach larvae also practice cannibalism. They will eat any dead siblings they find.

These insects need to grow in size with every molt. They need to produce a considerable amount of biomass in the process. Resources may be too scarce to fulfill this need, or too many dangers may prevent them from seeking out food. In these cases, they’ll take their siblings as the next best thing.

do cockroaches eat one another?

Do Cockroaches Eat Their Own Eggs?

If you thought nymphs provided a decent amount of nutrients, then you can be sure eggs do as well. Roaches will consume their own eggs if food is scarce.

This is partly why mother roaches to hide their egg sacs. They will be placed in dark, out-of-the-way locations, sometimes beyond the reach of the nest itself. This ensures that overpopulation is less likely to cull off the next generation. However, if driven to extreme hunger, the mothers are happy to seek out the eggs once more and consume them.

Nymphs may also eat their younger brethren while they’re still in egg form. These eggs are soft in comparison to hatched or adult roaches, making the process easier. The eggs will also be entirely unable to defend themselves.

Do Cockroaches Eat Their Own Poop?

Cockroaches are known to regularly eat the feces of other animals. Disgusting as it seems, there are plenty of nutrients to be found in animal waste for a cockroach. Do cockroaches eat their own poop, though? The Medical Entomology and Zoology says no, unless they are starving and have no other options available.

That’s because cockroach poop has very few nutrients in it. Unlike certain animals, which recycle feces (or poop-like cecotropes) into their diet, roaches cannot sustain themselves off that material. Instead, they rely on the feces of other, usually larger animals. That’s because these can expend a greater amount of trace vitamins, minerals, fats, or proteins into their waste. A small roach, on the other hand, which is designed to recycle what no other creature wants, has no such luxury. 

In an experiment using smoky-brown cockroaches, scientists found that cockroaches would resort to cannibalism before coprophagy. Even then, eating their own feces drastically reduced the lifespan of the individuals.

Nonetheless, it has been noted that cockroach nymphs will eat their own feces. Scientists are still exploring why this option is more appealing to young roaches.  

Do Cockroaches Eat Molted Skins?

Cockroach nymphs will eat their own molts, and those of their siblings. Adult cockroaches will also eat shed molts. That’s because these skins retain an impressive amount of nutrients, even after they’re used up.

Among the nutrients is chitin, made of fiber and polysaccharides. This component is what makes exoskeletons so hard and durable. By consuming that otherwise wasted resource once more, roaches can add it back into their system. This will fortify their bodies to help create new skins in the future. After all, most will only molt their exoskeleton so they can grow in size – not because there was anything wrong with their meticulously crafted shell.

This is especially important for nymphs. They will need to molt another 13 times before completing their growth cycle. If they don’t develop a hardy shell, they’ll be easily cannibalized by other roaches.

Obviously, if there is a reliable food source nearby, the cockroach may simply leave its shed skin to rot.

Do Cockroaches Eat Other Insects?

Cockroaches are not picky eaters. Any dead insects that a cockroach finds will be a good meal. This includes shed skins, eggs, and larvae.

With that said, roaches are limited by the strength of their mandibles (or teeth). Their size in comparison to other bugs will also deter them. Beetles, for example, will be less appealing to a roach than flies. That’s because the cockroach must contend with the hard outer shell before it can properly consume the beetle. Even if it found a dead one, it may struggle to gnaw through its exoskeleton.

Roaches Aren’t Hunters

It’s also worth noting that roaches understand their position as prey in the food chain, not a predator. They will not tangle with stronger, more flexible, or otherwise more dangerous bugs. The risk to themselves is rarely, if ever, worth the trouble. Unappealing bugs to eat will include live centipedes, certain kinds of spiders, or scorpions. Exceptions may include:

  • Bugs that are injured (and therefore unable to fight or escape)
  • Bugs that are sickly
  • Bugs that are weakened by insecticide

However, this will always be a last resort. Even more easily dominated prey, like mites, flies, or ants, will be outside the cockroach’s normal realm of expertise.

Can You Make Roaches Eat Each Other?

Since these insects are willing to turn on their own kind, you may be curious: Can you use that to your advantage?

There’s no direct method of forcing roaches to eat each other. Despite using pheromones to influence each other’s actions, cockroaches lack any ‘attack at will’ signal that humans could manipulate.

You can limit a colony’s access to food, which will deter the infestation from settling in your home. For existing colonies, this lack of food will also motivate them to resort to cannibalism.

However, this is not an effective way to exterminate cockroaches. As clever and wonderful as it would be, you can’t make roaches do your dirty work.

Cannibalism And Poisoning

You can, however, use this brief moment of cannibalism to effectively poison the colony. This is done through roach traps that use a form of poisoned bait.

  • Once a roach consumes it, the insect may return to the colony and then be eaten.
  • The cockroach that eats this poisoned roach will then die as well.
  • Any cockroaches that use this opportunistic kill to snack on stray limbs or droppings may also die.

This is more time consuming than other methods, but it does make a dent. On the whole, roaches are willing and ready to eat anything they can get their mandibles around. This may include eating their young, each other, and even their own poop. If you leverage the right tools and timings, you can use this to deter or drive off an infestation.